Hands down the most posted question by people new to the swap pages is "How do I import swap files into RealFlight" or "Where do I put the files after I unzip a downloaded swap file". First off "DO NOT UNZIP ANY SWAP FILE" This is a problem mainly had by people who use Internet Explorer. IE will change the swap files to .zip files. RealFlight will import .rfx,.g3x, and .zip files. If you unzip the file and import the .kex within you will not have the physics that make the model fly correctly. Importing a kex is only for designers who are familiar with what they are doing. The average RealFlight user should simply disregard the "Import/KEX" portion of the importer.
The attached images will guide you through the process of importing an AV(Aircraft Variant) and it's !REQUIRED! EA(Entire Aircraft). An AV will not work or import without the EA it was derived from. The same thing discussed here is true for CS(Color Schemes) and RC(Recording) files. The EA is required for all files created using it.

Crashing while creating DDS
Newer user created content sometimes use large image files to color and detail the model. This can occasionally cause the sim to crash. You can increase your chances of a fully successful import by following these steps.

First delete the failed attempt.
A previous import attempt will prevent a fresh one. Go to Simulation/Manage User Files/Aircraft/Imported find the failed import and delete.

Restart Real Flight
This will unload Real Flight from memory therefore freeing up system resources.

Go to a photo field
A photofield is less memory intensive and takes up less system resources needed for the DDS creation process.

DO NOT fly any aircraft
Flying aircraft load up memory as well.

Import the g3x, rfx, or zip
As described in the first section in this post.

Restart Real Flight
This is just extra precaution.

Choose the aircraft from the list and DO NOT use your computer until the model spawns
Using the computer for unrelated tasks will again use resources during the crucial DDS file creation.

The swap files contain all of the EA`s and AV`s If you click on an AV file that you want, you will get a link to the EA file on that page, you`ll need to download that aircraft next to "requires" on that page, before your AV will import into RF.